What is most shocking about the mind-blowing, 645-horsepower, long-nosed 2015 Dodge Viper is how cuddly it is in stop-and-go city traffic. As easy to manage as a scooter, as comfortable as a living room La-Z-Boy.

How can this be? The car is a beast, a nasty cocktail of speed and handling. The engine is an 8.4-litre V-10 monster, the dampers are Bilsteins, the manual six-speed gearbox is an excellent short-throw and smooth TREMEC offering and the package boasts high-strength steel, magnesium, aluminum and carbon fibre.

From one metre or 50, the frightening Viper body is as instantly recognizable as Hells Angels colours. The hood’s cold-air intake speaks to the need for this baby to breathe. The Brembo brakes, with their 14-inch vented rotors and four-piston calipers, are cooled with the help of a gaping front air intake. And the dual side sport exhaust is as bold as it is functional.

I love driving this sheep in a beast’s clothing. Dip into the throttle and the gentle throbbing and grumbling builds into a violent, hammering growl. Shocking. Small children suffer nightmares from noises like this.

Yet the car itself is manageable and predictable. Tight, responsive and powerful? Sure. But your 90-year-old grandpop would find the fifth-generation Viper as user-friendly as the golf cart shuttle in his gated retirement community.

The only challenge: climbing down over the sill and into the snug two-seat cockpit. Grandpop needs to be spry and nimble for that bit of gymnastics.

Nimble ... and financially comfortable. The least-expensive Viper lists for $92,995, while the GTS version I drove goes for $114,995, plus options, fees and taxes. Not cheap.

Which means we’re looking at a toy for boomer boys in good shape. Look closely. This is the automotive equivalent of The Expendables – Stallone, Lundgren, Schwarzenegger. Pick one. That’s the 2015 Viper. A new/old muscle car.

Old because muscle cars are by definition anachronistic, and new because the package is modern, from the driver-selectable suspension system to four-mode electronic stability control to the composite intake manifold and seven-inch, LED-backlit in-cluster display. This is a 21st-century execution of a 20th-century concept.

How much longer will American car makers carry on with cars such as the Viper and the Dodge Challenger SRT Hellcat? Let’s be honest. The heyday of the muscle car was 40-odd years ago.

Do a search of the greatest muscle cars of all time, and what pops up? The 1970 Plymouth Hemi ’Cuda, the 1969 Ford Mustang Boss 429 and Chevrolet’s 1970 Chevelle SS 454. The Viper today is a successor to these and others like the 1967 Pontiac GTO.

Dodge must certainly have a Viper – this sort of hairy-chested machine oozing Americana – but for how long? It’s not likely to be around beyond the end of the decade. Boomer buyers for this sort of car are steadily heading to the edge of the demographic table, some even going over the side.

The challenge for Fiat Chrysler, Ford and General Motors is to redefine the Viper, the Shelby Ford Mustang and the Chevy Corvette over the next decade. That is under way.

Among the Detroit-based brands, Ford is arguably the furthest along. The new head of Ford Performance, the umbrella group for Ford’s racy cars, is Dave Pericak who, in his previous job, was chief engineer of the new Mustang. In that job, Pericak championed a four-cylinder EcoBoost Mustang to appeal to younger buyers who are almost universally unimpressed by boomers and traditional muscle cars.

Pericak’s group is responsible for the V-6 EcoBoost-powered GT supercar unveiled in January at the Detroit auto show. No V-8 or V-10 in this lightweight bomb.

So, will a future Shelby Mustang have an EcoBoost V-6 or four-cylinder? Bet on it. Market and regulatory pressures mean that, in time, the 21st-century muscle car will evolve into something electrified, a gasoline-electric hybrid. One day we may even define muscle by the size of the battery pack.

The V-10 Viper is likely the last of its kind. So happy to have known you.

I really want to own a Viper someday. And I don't mean the 645-hp late model coupe, but rather an early model roadster. I do not want it to have a hard top, but I do want it to have hot side exhaust. It doesn't need to be refined and comfortable, that defeats the point. I want the big motor, manual gears, loud exhaust and open air cockpit. OK, I'm drooling now...